Working example with start cancel

.vscode/launch.json

@@ -7,7 +7,8 @@
       "request": "launch",
       "runtimeExecutable": "${execPath}",
       "args": ["--extensionDevelopmentPath=${workspaceFolder}"],
-      "outFiles": ["${workspaceFolder}/out/**/*.js"]
+      "outFiles": ["${workspaceFolder}/out/**/*.js"],
+      "preLaunchTask": "npm: compile"
     }
   ]
 }

.vscode/tasks.json

@@ -0,0 +1,12 @@
+{
+  "version": "2.0.0",
+  "tasks": [
+    {
+      "label": "npm: compile",
+      "type": "shell",
+      "command": "npm run compile",
+      "group": "build",
+      "problemMatcher": []
+    }
+  ]
+}